Ch. 5 Flashcards
DNA is important because it’s an ____ and carries ___, which are most important of all biological knowledge bc it contains instructions for the function of every enzyme and cell in our bodies and carries the evolutionary history of cells/organisms
identifier; Genes
How can DNA serve as an individual identifier?
every person’s DNA is unique and leaves a trail of DNA behind us as we go about lives
DNA is which type of macromolecule
nucleic acid
-nucleic acids store info, DNA stores genetic info
nucleotides are made up of what
three components: a molecules of sugar, a phosphate group, and a nitrogen containing molecule called a base
base
nitrogen containing molecule
what are the “backbones” of DNA
two distinct strands, like the vertical sides of a ladder
what are the “backbones” made up of
two alternating molecules: sugar and a phosphage group (then sugar then a phosphate group)
sugar is always..
deoxyribose
what is the role of the alternating sugars and phosphates
support
what’s important about the rungs of the ladders in DNA
one of four bases: adenine, thymine, cytosine, and guanine or A,T,C,G
THE BASES BIND TO THE LADDER VIA WHAT
HYDROGEN BONDS AND BASE PAIRS
A pairs with
T
C pairs with
G
does the sugar backbone convey genetic information?
no, it holds the base sequences
why is DNA considered the universal code for all life on earth?
it embodies the instructions for building the cells and structures for almost every single living organism on earth
An organism’s _____ is similar to a cookbook
DNA;
why is DNA like a cookbook
cookbooks contain detailed instructions on how to make a variety of foods/dishes, and an organism’s DNA carries the detailed instructions to build an organism and keep it running
How does a DNA sequence be viewed as a code?
by the nucleotide base pairs, the dna makes up a code that holds the instructions for the building of the organism
genome
full set of dna present in an individual organism
how are DNA stored in prokaryotes and bacteria?
in circular peices
how is DNA stored in eukaryotes and humans?
Chromosomes, strands of DNA; humans have 23 and two copies of each, so 46. (copy from mom and dad)
locus/loci
location or position of a gene on a chromosone
gene
sequence of bases/base pairs in a DNA molecule that carries info for producing a functional product, usually a polypeptide or RNA molecule
each gene is the instruction set for producing one particular molecule, usually a what
protein
how come there are different versions of the same characteristic?
some individuals have slightly different instructions sets for a given protein, and the instructions result in different versions of the same characteristic
alleles
alternative versions of a gene that code for the same feature
trait
any single characteristic or feature of an organism
describe relationship between the size of an organism’s genome and the organism’s complexity
there isn’t one
non-coding DNA was known as
junk DNA
what type of organisms have the most “junk DNA”?
Euakryotes
introns
where 25% of the non-coding regions occur within genes
about 75%of the non-coding regions occur where
between genes
what have scientists found out about noncoding dna?
encodes extremely short RNA molecules.. about twenty nucleotides long that function in gene regulation
transcription
copy of a gene’s base sequence is made
translation
the copy that was just made in transcription is used to direct the production of a polypeptide, which then, in a response to a variety of factors, including the cellular environment, folds into a functional protein
where are the base pairs/code copied during transcription in eukaryotes?
the middle man molecule called messenger RNA aka mRNA
where does transcription occur in prokaryote4s
cytoplasm bc it doesnt have a nucleus
where does transcription occur in eukaryotes?
nucleus
what is done with the copy made in translation?
used to direct the production of a polypeptide
In transcription, the info coded in DNA is copied into what
mRNA
If dna is like a cookbook filled with recipes, transcription and translation are like what
cooking
step 1 of transcription
recognize and bind
Enzyme RNA polymerase recognizes a promoter site which tells teh RNA polymerase to “start here.” RNA polymerase then binds to the DNA molecule at the promoter site and unwinds it a little bit so that one strand of DNA could be read
Promoter site
sequence in a gene that indicates the start of a gene
step 2 of transcription
transcribe
as dna is being processed through the RNA polymerase, the RNA polymerase builds a copy called a “transcript” of the gene from the dna molecule. the copy becomes a messenger RNA bc once the copy of the gene is created, it can move elsewhere in the cell and its message can be translated into a protein
what’s different about the pairing bases in transcription?
a pairs with u, uracil
step three of transcription
terminate
once the rna polymerase comes to the termination sequence, it stops creating the transcript and detaches from the dna molecule
termination sequence
sequence of bases on DNA at the end of a gene
what happens after termination to the mrna molecule?
becomes a free-floating, single-strand copy of the gene
step four of transcription
capping and editing
extra processing before translated into a protein; the cap and tail are added at the beginning and end of the transcri[pt, like the fron and back covers of a book
does step four of transcription occur in all cells?
in prokaryotes the dna is ready to be translated into a protein bc it doesnt have a nuclear membrane to cross, but in eukaryotes mrnas have to do the extra step because of their nuclear membrane
